Electrostatic spray powder coating processes have been used in commercial and industrial applications for some time. In general, powder coating involves electrically grounding a part, spraying the part with a powder coating that has been positively charged, and then thermally curing the powder coating at elevated temperatures.
In some powder coating processes, parts are manually hung onto an overhead conveyor system. The parts are then conveyed through the various cleaning, powder coating, and curing stages of the powder coating process. Because the parts are hanging vertically, the paint or coating deposits tend to be heavier toward the lower end of the part. This uneven distribution is due at least in part to gravitational issues associated with airborne power paint, for example, settling lower in the paint booth. Uneven distribution can result in the parts having areas with too thin of a powder coating or too thick of a powder coating.
In general, such surface treatment processes and systems can be improved.